1. Field of the Invention
The present invention relates to an apparatus for reproducing audio data or video data out of a recording medium which is equally divided into a plurality of storage units each having a predetermined capacity. More particularly, the present invention is concerned with an audio/video data reproducing apparatus capable of transferring data read out of the recording medium to external equipment over a communication path.
2. Description of the Background
It is a common practice with a semiconductor memory or similar memory to record video data or audio data therein after coding by compression in order to reduce the amount of data to be recorded. The semiconductor memory may be equally divided into a plurality of storage units, or clusters, each having a predetermined capacity, as proposed by the same applicant as the present application and disclosed in Japanese patent application No. 10997/1989 by way of example. In such a case, one or more of the clusters of the memory are used to record desired audio data or video data.
Specifically, the recording scheme disclosed in the above Japanese patent application divides a memory into a plurality of clusters and uses the first cluster for storing supervisory data and the others for recording video data. The memory has a supervisory data area which is assigned to a directory and a memory allocation table (MAT). When compressed image data is to be recorded in a plurality of clusters, for example, the number assigned to the cluster to record the leading video data is written into the directory of the supervisory area while the number assigned to the cluster immediately following the above-mentioned cluster is written into the MAT. Video data is written in and read out of the memory with reference being made to such supervisory data.
For example, to record new video data in the memory, the number of clusters necessary to accommodate the video data is determined, and then more than such a number of non-recorded or empty clusters available in the memory are searched for. Thereafter, the video data are sequentially recorded in the empty clusters. On the other hand, to read desired video data out of the memory, recorded or full clusters storing the video data of interest are searched for in memory beforehand, and then the video data are reproduced.
The conventional audio/video data reproducing apparatus described above has some problems left unsolved, as follows. Assume that audio data or video data are transferred from the reproducing apparatus to a word processor or similar external equipment which is connected to the apparatus by a communication path. Then, as a communication error occurs on the communication path or in the equipment connected to the communication path while the data transfer is under way, it is necessary that all the data of the cluster reached at that moment be transferred again to the equipment afterwards. At this instant, the coventional reproducing apparatus is required to set the address data of such a particular cluster all over again. In addition, even when desired data such as video data have been fully read out of an expected number of clusters and transferred from the reproducing apparatus to the external equipment, the reproducing apparatus cannot recognize the end of transfer of the data to the external equipment.